NATURALISTS’ FIELD CLUB

Evening Star, Issue 19615, 22 July 1927, Page 9

NATURALISTS’ FIELD CLUB

SATURDAY’S OUTING The purpose of tho afternoon’s excursion on Saturday last was to observe the disposition of tho sedimentary rocks around Dunedin. The club travelled by corporation bus along the Main South road to Abbotsford, stopping at various points ’on tho journey to examine the outcrops which there occurred. A chart had been prepared to show the sequence to bo expected, ami they were: On,top of Look-out Point, volcanic rocks; beside the road as it descended into Burnside, Caycrsham sandstone; at Green island, first the marl surmounted by a dark baud ol greens in the Cement Company’s quarry, and then loose sands in a quarry a - little further on. It was noted in these two outcrops that the strata were dipping gently to the oast. Then at Abbotsford was seen * the mudstone, and finally, in Fcrnhill Creek, were seen the coal seams and associated sands resting the fundamental schist. The general characteristics of these sediments, their agcs ; and conditions ot depositions and relations to other parts of the country wore discussed. A visit was then paid to tho Kaikorai lagoons, where the raised beaches were noted and their origin explained. The nartv was under tho leadership of Mr H. S. Tily. INDOOR MEETING. At the indoor meeting held on Monday evening Dr Holyloway gave a very interesting and .instructive lecture on lichens. The lecturer stated that lichens belonged to those simpler forms of plants known as Thallophytes —that was to say, plants which had an indifferen ,i----ated or unorganised plant body. ’I hey grew chiefly on the bark of trees, or on old palings, walls, etc. In some instances they presented a dry, shrivelled, more or less tilelcss appearance, and sometimes they appeared as a mere coloring on boulders as if painted on. They were distributed in - all parts of tho a Id. The pulverulent species were the first plants to clothe the bare rocks of newly-formed islands in the midst of the ocean. Foliaceous lichens followed these, then mosses and liverworts. They also formed a considerable proportion of the vegetation ot the polar regions and of mountain tops. Dr Holloway, however, roused the interest of his audience by stating that lichens were of tho vegetable kingdom, an extraordinary phenomenon, being dual plants consisting of a fungus and an algae. It was a case of symbiosis, two plants living together for a social benefit. For a long time this was not generally known. In analysing the plant, early scientists saw the algae cells, but thought they were reproductory organs. Even yet there -were quite a number of licbenologists who doubted the fact, and American botanists said that it was just another instance ol fungus being parasitic, this time a menial case—i.e., fungus parasitic on algae. Dr Holloway, however, preferred to deal with it as a case ox symbiosis, ol which there were many instances in the plant and animal kingdom, instances of symbiosis were even known in animals and plants. The mutual benefits derived were stated to be, first, the fungus gave protection to the algae, and also handed on to the algae salts and water derived from tho soil, while in turn the algae passed on sugar food to the fungus. Lichens had actually been built up in laboratories by man, which fact was straight-out evidence that there were two plants. Dr Hollowav stated that New Zealand lichens wore" bv no means thoroughly known ; hence ho would attempt to give only a general account of tho life history ot a few typical New Zealand genera. In some lichens the . fungus threads permeated throughout all the body, and in others it was in lawyers. By those means they were classified as—(l) Stratified, (2) unstratified; 95 per cent. belonged to the latter. They were a train divided into three main groups; (1) Crustaccous lichens, growing on boulders (numerous); (2) foliosc lichens, fiat, leafy; (3) fruticosc lichens, erect growing. The methods of reproduction and the reproductory organs of these trnlv wonderful plants were also dealt with, the latter being illustrated witl/ lantern slides. A benrtv vote of thanks was accorded Dr Holloway for his very interesting lecture.